Porphyry Cu(Mo-Au)deposit is one of the most important types of copper deposit and usually formed under magmatic arc-related settings,whilst the Mujicun porphyry Cu-Mo deposit in North China Craton uncommonly generate...Porphyry Cu(Mo-Au)deposit is one of the most important types of copper deposit and usually formed under magmatic arc-related settings,whilst the Mujicun porphyry Cu-Mo deposit in North China Craton uncommonly generated within intra-continental settings.Although previous studies have focused on the age,origin and ore genesis of the Mujicun deposit,the ore-forming age,magma source and tectonic evolution remain controversial.Here,this study targeted rutile(TiO_(2))in the ore-hosting diorite porphyry from the Mujicun Cu-Mo deposit to conduct in situ U-Pb dating and trace element composition studies,with major views to determine the timing and magma evolution and to provide new insights into porphyry Cu-Mo metallogeny.Rutile trace element data show flat-like REE patterns characterized by relatively enrichment LREEs and depleted HREEs,which could be identified as magmatic rutile.Rutile U-Pb dating yields lower intercept ages of 139.3–138.4 Ma,interpreted as post magmatic cooling timing below about 500℃,which are consistent or slightly postdate with the published zircon U-Pb ages of diorite porphyry(144.1–141.7 Ma)and skarn(146.2 Ma;139.9 Ma)as well as the molybdenite Re-Os ages of molybdenum ores(144.8–140.0 Ma).Given that the overlap between the closure temperature of rutile U-Pb system and ore-forming temperature of the Mujicun deposit,this study suggests that the ore-forming ages of the Mujicun deposit can be constrained at 139.3–138.4 Ma,with temporal links to the late large-scale granitic magmatism at 138–126 Ma in the Taihang Orogen.Based on the Mg and Al contents in rutile,the magma of ore-hosting diorite porphyry was suggested to be derived from crust-mantle mixing components.In conjunction with previous studies in Taihang Orogen,this study proposes that the far-field effect and the rollback of the subducting Paleo-Pacific slab triggered lithospheric extension,asthenosphere upwelling,crust-mantle interaction and thermo-mechanical erosion,which jointly facilitated the formation of dioritic magmas during the Early Cretaceous.Subsequently,the dioritic magmas carrying crust-mantle mixing metallic materials were emplaced and precipitated at shallow positions along NNE-trending ore-controlling faults,eventually resulting in the formation of the Mujicun Cu-Mo deposit within an intracontinental extensional setting.展开更多
Plastic scintillators(PSs)embedded with wavelength-shifting fibers are widely used in high-energy particle physics,such as in muon taggers,as well as in medical physics and other applications.In this study,a simulatio...Plastic scintillators(PSs)embedded with wavelength-shifting fibers are widely used in high-energy particle physics,such as in muon taggers,as well as in medical physics and other applications.In this study,a simulation package was built to evaluate the effects of the diameter and layout of optical fibers on the light yield with different configurations.The optimal optical configuration was designed based on simulations and validated using two PS prototypes under certain experimental condi-tions.A top veto tracker(TVT)for the JUNO-TAO experiment,comprising four layers of 160 strips of PS,was designed and evaluated.The threshold was evaluated when the muon tagging efficiency of a PS strip was>99%.The efficiency of three layer out of four layer of TVT is>99%,even with a tagging efficiency of a single strip as low as 97%,using a threshold of 10 photoelectrons and assuming a 40%silicon PM photon detection efficiency.展开更多
MicroRNA (miR)-125b has been shown to play a potential role in the development of glioma stem cells.However,the relationship between miRNA and glioma stem cells is still elusive.This study was designed to elucidate th...MicroRNA (miR)-125b has been shown to play a potential role in the development of glioma stem cells.However,the relationship between miRNA and glioma stem cells is still elusive.This study was designed to elucidate this potential relationship.We established a highly invasive glioma stem cell and progenitor (GSCP) cell line SU3.SU3 cell suspensions were injected into nude mice brains in situ,and the invasiveness of graft tumors was analyzed using hematoxylin and eosin staining as well as immunohistochemistry.Real-time polymerase chain reaction (PCR) was used to measure the expression levels of miR-125b in SU3 and other cells.In vitro,SU3 cells expressed CD133 and nestin as well as differentiation markers glial fibrillary acidic protein (GFAP) and β-tubulin III,which were consistent with the characteristics of glioma stem cells.Scratch assays indicated that the migration ability of SU3 cells was stronger than that of U251 stem cells (U251s).In vivo,SU3 cells invaded into each part of the mouse brain from the caudate nucleus in a diffuse pattern and highly expressed invasive and proliferative cell markers matrix metalloprotease 2 (MMP2),MMP9,and Ki-67.Real-time PCR results revealed that the levels of miR-125b and MMP9 were significantly higher in SU3 and SU2,also a highly invasive GSCP cell line we established before,than in U251s.High expression of miR-125b both in newly established GSCPs,SU3,and long-term cultured GSCPs,SU2 suggests that miR-125b exhibits oncogene-like behavior.This behavior should be considered in further studies of miR-125b in cancer stem cells.Furthermore,MMP9,which plays a role in cancer stem cell invasion,may be a target gene of miR-125b.展开更多
Spectral beam combining is an effective way to achieve high-brightness direct diode laser output.We present an experimental study on spectral beam combining with external cavity based on transmission grating.Using a s...Spectral beam combining is an effective way to achieve high-brightness direct diode laser output.We present an experimental study on spectral beam combining with external cavity based on transmission grating.Using a series of cylindrical transform lenses with different focal lengths,spectral beaming combining efficiency is greatly improved,and the results of wavelength intervals are consistent with the theoretical calculations.With the injection current of 90 A,a 75.1 W cw 930 nm output power with wavelength span of 18.6 nm and spectral beam combining efficiency of 92.7%is achieved,the beam parameter product is 5.77 mm·mrad.展开更多
By partially doping Pb to effectively suppress the superstructure in single-layered cuprate Bi_2Sr_2CuO_(6+δ)(Pb-Bi2201) and annealing them in vacuum or in high pressure oxygen atmosphere, a series of high quality Pb...By partially doping Pb to effectively suppress the superstructure in single-layered cuprate Bi_2Sr_2CuO_(6+δ)(Pb-Bi2201) and annealing them in vacuum or in high pressure oxygen atmosphere, a series of high quality Pb-Bi2201 single crystals are obtained with T_c covering from 17 K to non-superconducting in the overdoped region. High resolution angle resolved photoemission spectroscopy measurements are carried out on these samples to investigate the evolution of the Fermi surface topology with doping in the normal state. Clear and complete Fermi surfaces are observed and quantitatively analyzed in all of these overdoped Pb-Bi2201 samples. A Lifshitz transition from holelike Fermi surface to electron-like Fermi surface with increasing doping is observed at a doping level of ~0.35. This transition coincides with the change that the sample undergoes superconducting-to-non-superconducting states.Our results reveal the emergence of an electron-like Fermi surface and the existence of a Lifshitz transition in heavily overdoped Bi2201 samples. This provides important information in understanding the connection between the disappearance of superconductivity and the Lifshitz transition in the overdoped region.展开更多
A database system,known as the large PMT characterization and instrumentation database system(LPMT-CIDS),was designed and implemented for the Jiangmen Underground Neutrino Observatory(JUNO).The system is based on a Li...A database system,known as the large PMT characterization and instrumentation database system(LPMT-CIDS),was designed and implemented for the Jiangmen Underground Neutrino Observatory(JUNO).The system is based on a Linux+Apache+MySQL+PHP(LAMP)server and focuses on modularization and architecture separation.It covers all the testing stages for the 20-inch photomultiplier tubes(PMTs)at JUNO and provides its users with data storage,analysis,and visualization services.Based on the successful use of the system in the 20-inch PMT testing program,its design approach and construction elements can be extended to other projects.展开更多
We report a high conversion efficiency Q-switched Nd:YVO_4/KTiOAsO_4(KTA) intracavity optical parametric oscillator(IOPO) operating near 3.5 um based on direct 880 nm laser diode(LD) pumping. A maximum average idler o...We report a high conversion efficiency Q-switched Nd:YVO_4/KTiOAsO_4(KTA) intracavity optical parametric oscillator(IOPO) operating near 3.5 um based on direct 880 nm laser diode(LD) pumping. A maximum average idler output power of 2.6 W with a pulse width of about 7.9 ns is achieved under an absorbed LD power of 45.4 W at a pulse repetition rate(PRR) of 10 kHz. The maximum optical-optical conversion efficiency from LD power to OPO mid-infrared(MIR) output of 6.74% is achieved. To our knowledge, this is the highest conversion efficiency for a KTA-IOPO by exploiting a Q-switched laser as the parent fundamental pump source. The beam quality factors M^2 of the MIR beam at the full output power with a PRR of 10 kHz are within 2.12 in both the horizontal and vertical directions, indicating a near Gaussian mode.展开更多
We report on the experimental investigation and theoretical analysis of a nanosecond pulse high power ultraviolet（UV） 278 nm laser by fourth-harmonic generation（FHG） of a 1112-nm Nd：YAG amplifier in LiB3O5（LBO）...We report on the experimental investigation and theoretical analysis of a nanosecond pulse high power ultraviolet（UV） 278 nm laser by fourth-harmonic generation（FHG） of a 1112-nm Nd：YAG amplifier in LiB3O5（LBO） and CsB3O5（CBO） crystals. The UV laser delivers a maximum average power of 10.3 W at 278 nm with peak power of 36.8 k W under input pump power of 41 W at 556 nm. This is, to the best of our knowledge, the highest output power at the specific UV wavelength of 278 nm. We also performed the theoretical investigation on the FHG with a model in the Gaussian approximation of both spatial and temporal profiles, especially accounting for the two-photon absorption effect in CBO crystal for the first time. The average output power, pulse width, and beam spatial distribution of the UV laser were simulated. The theoretical calculations are in close agreement with the experimental results.展开更多
A novel high-energy picosecond optical parametric oscillator(OPO)was realized by placing an OPO in a secondharmonic(SH)cavity.In a proof-of-principle experiment,we demonstrated excellent burst energy of 45μJ for the ...A novel high-energy picosecond optical parametric oscillator(OPO)was realized by placing an OPO in a secondharmonic(SH)cavity.In a proof-of-principle experiment,we demonstrated excellent burst energy of 45μJ for the OPO signal at 900 nm that operates at a pulse repetition rate of 10 k Hz and a pulse width of 46.8 ps.The beam quality was measured as M_(x)^(2)=1.44 and M_(y)^(2)=1.40 in the orthogonal directions,corresponding to an average beam factor M^(2)=1.42.So far,this study is the first to investigate high-energy ps OPO synchronously pumped in a second-harmonic cavity.展开更多
WTe2 has attracted a great deal of attention because it exhibits extremely large and non-saturating magnetore- sistance. The underlying origin of such a giant magnetoresistance is still under debate. Utilizing laser-b...WTe2 has attracted a great deal of attention because it exhibits extremely large and non-saturating magnetore- sistance. The underlying origin of such a giant magnetoresistance is still under debate. Utilizing laser-based angle-resolved photoemission spectroscopy with high energy and momentum resolutions, we reveal the complete electronic structure of WTe2. This makes it possible to determine accurately the electron and hole concentrations and their temperature dependence. We find that, with increasing the temperature, the overall electron concen- tration increases while the total hole concentration decreases. It indicates that the electron-hole compensation, if it exists, can only occur in a narrow temperature range,and in most of the temperature range there is an electron-hole imbalance. Our results are not consistent with the perfect electron-hole compensation picture that is commonly considered to be the cause of the unusual magnetoresistance in WTe2. We identify a fiat band near the Brillouin zone center that is close to the Fermi level and exhibits a pronounced temperature dependence. Such a fiat band can play an important role in dictating the transport properties of WTe2. Our results provide new insight on understanding the origin of the unusual magnetoresistance in WTe2.展开更多
Haemangiopericytoma(HPC) is a rare vascular tumor with borderline malignancy, considerable histological variability, and unpredictable clinical and biological behavior. HPC can present a diagnostic challenge because o...Haemangiopericytoma(HPC) is a rare vascular tumor with borderline malignancy, considerable histological variability, and unpredictable clinical and biological behavior. HPC can present a diagnostic challenge because of its indeterminate clinical, radiological, and pathological features. HPC generally presents in adulthood and is equally frequent in both sexes. HPC can arise in any site in the body as a slowly growing and painless mass. The precise cell type origin of HPC is uncertain. One third of HPCs occur in the head and neck areas. Exceptional cases of hemangioblastoma arising outside the head and neck areas have been reported, but little is known about their clinicopathologic and immunohistochemical features. This study reports on a case of a large sacro-anterior HPC in a 65-year-old male.展开更多
We carry out detailed momentum-dependent and temperature-dependent measurements on Bi_(2)Sr_(2)CaCu_(2)O_(8+δ)(Bi2212)superconductor in the superconducting and pseudogap states by super-high resolution laser-based an...We carry out detailed momentum-dependent and temperature-dependent measurements on Bi_(2)Sr_(2)CaCu_(2)O_(8+δ)(Bi2212)superconductor in the superconducting and pseudogap states by super-high resolution laser-based angleresolved photoemission spectroscopy.The precise determination of the superconducting gap for the nearly optimally doped Bi2212(T_(c)=91 K)at low temperature indicates that the momentum-dependence of the superconducting gap deviates from the standard d-wave form(cos(2Φ)).It can be alternatively fitted by including a high-order term(cos(6Φ))in which the next nearest-neighbor interaction is considered.We find that the band structure near the antinodal region smoothly evolves across the pseudogap temperature without a signature of band reorganization which is distinct from that found in Bi_(2)Sr_(2)CuO_(6+δ)superconductors.This indicates that the band reorganization across the pseudogap temperature is not a universal behavior in cuprate superconductors.These results provide new insights in understanding the nature of the superconducting gap and pseudogap in high-temperature cuprate superconductors.展开更多
Glucosinolates are amino acid-derived secondary metabolites that act as chemical defense agents against pests.However,the presence of high levels of glucosinolates severely diminishes the nutritional value of seed mea...Glucosinolates are amino acid-derived secondary metabolites that act as chemical defense agents against pests.However,the presence of high levels of glucosinolates severely diminishes the nutritional value of seed meals made from rapeseed(Brassica napus L.).To identify the loci affecting seed glucosinolate cont ent(SGC),we con ducted genome-wide resequencing in a population of 307 diverse B.napus accessions from the three B.napus ecotype groups,namely,spring,winter,and semi-winter.These resequencing data were used for a genome-wide association study(GWAS)to identify the loci affecting SGC.In the three ecotype groups,four comm on and four ecotype-specific haplotype blocks(HBs)were significantly associated with SGC.To identify candidate genes controlling SGC,transcriptome analysis was carried out in 36 accessions showing extreme SGC values.Analyses of haplotypes,genomic variation,and candidate gene expression pointed to five and three candidate genes in the common and spring group-specific HBs,respectively.Our expression analyses dem on strated that additive effects of the three candidate genes in the spring group-specific HB play important roles in the SGC of B.napus.展开更多
Endogenous small RNAs are newly identified players in plant immune responses, yet their roles in rice （Oryza sativa） responding to pathogens are still less understood, especially for pathogens that can cause severe ...Endogenous small RNAs are newly identified players in plant immune responses, yet their roles in rice （Oryza sativa） responding to pathogens are still less understood, especially for pathogens that can cause severe yield losses. We examined the small RNA expression profiles of rice leaves at 2, 6, 12, and 24 hours post infection ofXanthomonas oryzae pv. oryzae （Xoo） virulent strain PXO99, the causal agent of rice bacterial blight disease. Dynamic expression changes of some miRNAs and trans-acting siRNAs were identified, together with a few novel miRNA targets, including an RLK gene targeted by osa-miR159a. 1. Coordinated expression changes were observed among some small RNAs in response to Xoo infection, with small RNAs exhibiting the same expression pattern tended to regulate genes in the same or related signaling pathways, including auxin and GA signaling pathways, nutrition and defense-related pathways. These findings reveal the dynamic and complex roles of small RNAs in rice-Xoo interactions, and identify new targets for regulating plant responses to Xoo.展开更多
We briefly review recent results on photoemission spectroscopy based on the deep and vacuum ultraviolet diode pumped solid-state lasers which we have developed.Cascaded second harmonic generation with the nonlinear cr...We briefly review recent results on photoemission spectroscopy based on the deep and vacuum ultraviolet diode pumped solid-state lasers which we have developed.Cascaded second harmonic generation with the nonlinear crystal KBe2BO3F2(KBBF)is used to generate deep ultraviolet and vacuum ultraviolet laser radiation,which complements traditional incoherent light sources such as gas discharge lamps and synchrotron radiation,and has greatly improved resolution with respect to energy,momentum,and spin of photoemission spectroscopy.Many new functions have been developed with the advantages of high photon energy,narrow linewidth,high photon flux density,and so on.These have led to the observation of various new phenomena and the amassment of new data in the fields of high temperature superconductivity,topological electronics,Fermi semi-metals,and so forth.These laser systems have revived the field of photoemission spectroscopy and provided a new platform in this frontier research field.展开更多
The insect nicotinic acetylcholine receptor(nAChR)is a pentameric channel protein and also a target for neonicotinoids.There are few reported studies on the molecular interactions of Leptinotarsa decemlineata nAChRs w...The insect nicotinic acetylcholine receptor(nAChR)is a pentameric channel protein and also a target for neonicotinoids.There are few reported studies on the molecular interactions of Leptinotarsa decemlineata nAChRs with neonicotinoids.In this study,we analyzed the response of acetylcholine and neonicotinoids(thiamethoxam[TMX],imidacloprid[IMI],and clothianidin[CLO])on hybrid receptors constructed by nAChRα1 andα8 subunits of L.decemlineata(Ldα1 and Ldα8)co-expressed with ratβ2 subunit(rβ2)at different capped RNA(cRNA)ratios in Xenopus oocytes.In addition,we evaluated the expression changes of Ldα1 and Ldα8 after median lethal dose of TMX treatment for 72 h by quantitative polymerase chain reaction(qPCR).The resulting functional nAChRs Ldα1/rβ2 and Ldα1/Ldα8/rβ2 showed different pharmacological characteristics.The neonicotinoids tested showed lower agonist affinity on Ldα1/Ldα8/rβ2 compared to Ldα1/rβ2 at same ratios of subunit cRNAs.The sensitivities of neonicotinoids tested for Ldα1/rβ2 and Ldα1/Ldα8/rβ2 at cRNA ratios of 5:1,1:1 and 5:5:1,1:1:1,respectively,were lower than those for nAChRs at ratios of 1:5 and 1:1:5,respectively,whereas the values of maximum response(Imax)varied.For Ldα1/Ldα8/rβ2,a reduction of Lda8 cRNA resulted in increased sensitivity to IMI and decreased sensitivity to TMX.The expression of Ldα1 and Ldα8 significantly decreased in adults by 82.12%and 47.02%,respectively,while Ldα8 was significantly upregulated by 2.44 times in 4th instar larvae after exposure to TMX.We infer that Ldα1 and Ldα8 together play an important role in the sensitivity of L.decemlineata to neonicotinoids.展开更多
基金jointly supported by the National Natural Science Foundation of China(4220207742103025)+5 种基金the Opening Foundation of MNR Key Laboratory of Metallogeny and Mineral Assessment(ZS2209ZS2106)the Opening Foundation of Key Laboratory of Mineral Resources in Western China(Gansu Province)(MRWCGS-2021-01)the Natural Science Foundation of Gansu Province(22JR5RA440)the Fundamental Research Funds for the Central Universities(LZUJBKY-2022-42)the Guiding Special Funds of“Double First-Class(First-Class University&First-Class Disciplines)”(561119201)of Lanzhou University,China。
文摘Porphyry Cu(Mo-Au)deposit is one of the most important types of copper deposit and usually formed under magmatic arc-related settings,whilst the Mujicun porphyry Cu-Mo deposit in North China Craton uncommonly generated within intra-continental settings.Although previous studies have focused on the age,origin and ore genesis of the Mujicun deposit,the ore-forming age,magma source and tectonic evolution remain controversial.Here,this study targeted rutile(TiO_(2))in the ore-hosting diorite porphyry from the Mujicun Cu-Mo deposit to conduct in situ U-Pb dating and trace element composition studies,with major views to determine the timing and magma evolution and to provide new insights into porphyry Cu-Mo metallogeny.Rutile trace element data show flat-like REE patterns characterized by relatively enrichment LREEs and depleted HREEs,which could be identified as magmatic rutile.Rutile U-Pb dating yields lower intercept ages of 139.3–138.4 Ma,interpreted as post magmatic cooling timing below about 500℃,which are consistent or slightly postdate with the published zircon U-Pb ages of diorite porphyry(144.1–141.7 Ma)and skarn(146.2 Ma;139.9 Ma)as well as the molybdenite Re-Os ages of molybdenum ores(144.8–140.0 Ma).Given that the overlap between the closure temperature of rutile U-Pb system and ore-forming temperature of the Mujicun deposit,this study suggests that the ore-forming ages of the Mujicun deposit can be constrained at 139.3–138.4 Ma,with temporal links to the late large-scale granitic magmatism at 138–126 Ma in the Taihang Orogen.Based on the Mg and Al contents in rutile,the magma of ore-hosting diorite porphyry was suggested to be derived from crust-mantle mixing components.In conjunction with previous studies in Taihang Orogen,this study proposes that the far-field effect and the rollback of the subducting Paleo-Pacific slab triggered lithospheric extension,asthenosphere upwelling,crust-mantle interaction and thermo-mechanical erosion,which jointly facilitated the formation of dioritic magmas during the Early Cretaceous.Subsequently,the dioritic magmas carrying crust-mantle mixing metallic materials were emplaced and precipitated at shallow positions along NNE-trending ore-controlling faults,eventually resulting in the formation of the Mujicun Cu-Mo deposit within an intracontinental extensional setting.
基金supported by the School of Physics at Sun Yat-sen University,China
文摘Plastic scintillators(PSs)embedded with wavelength-shifting fibers are widely used in high-energy particle physics,such as in muon taggers,as well as in medical physics and other applications.In this study,a simulation package was built to evaluate the effects of the diameter and layout of optical fibers on the light yield with different configurations.The optimal optical configuration was designed based on simulations and validated using two PS prototypes under certain experimental condi-tions.A top veto tracker(TVT)for the JUNO-TAO experiment,comprising four layers of 160 strips of PS,was designed and evaluated.The threshold was evaluated when the muon tagging efficiency of a PS strip was>99%.The efficiency of three layer out of four layer of TVT is>99%,even with a tagging efficiency of a single strip as low as 97%,using a threshold of 10 photoelectrons and assuming a 40%silicon PM photon detection efficiency.
基金funded by grants from the Natural Science Foundation of China(NO.81172400,81000963)the Natural Science Foundation of Jiangsu Province(NO.BK2011341)the Natural Science Foundation of Suzhou(NO.SYS201063,SYS201161)
文摘MicroRNA (miR)-125b has been shown to play a potential role in the development of glioma stem cells.However,the relationship between miRNA and glioma stem cells is still elusive.This study was designed to elucidate this potential relationship.We established a highly invasive glioma stem cell and progenitor (GSCP) cell line SU3.SU3 cell suspensions were injected into nude mice brains in situ,and the invasiveness of graft tumors was analyzed using hematoxylin and eosin staining as well as immunohistochemistry.Real-time polymerase chain reaction (PCR) was used to measure the expression levels of miR-125b in SU3 and other cells.In vitro,SU3 cells expressed CD133 and nestin as well as differentiation markers glial fibrillary acidic protein (GFAP) and β-tubulin III,which were consistent with the characteristics of glioma stem cells.Scratch assays indicated that the migration ability of SU3 cells was stronger than that of U251 stem cells (U251s).In vivo,SU3 cells invaded into each part of the mouse brain from the caudate nucleus in a diffuse pattern and highly expressed invasive and proliferative cell markers matrix metalloprotease 2 (MMP2),MMP9,and Ki-67.Real-time PCR results revealed that the levels of miR-125b and MMP9 were significantly higher in SU3 and SU2,also a highly invasive GSCP cell line we established before,than in U251s.High expression of miR-125b both in newly established GSCPs,SU3,and long-term cultured GSCPs,SU2 suggests that miR-125b exhibits oncogene-like behavior.This behavior should be considered in further studies of miR-125b in cancer stem cells.Furthermore,MMP9,which plays a role in cancer stem cell invasion,may be a target gene of miR-125b.
基金National Natural Science Foundation of China under Grant No.61535013。
文摘Spectral beam combining is an effective way to achieve high-brightness direct diode laser output.We present an experimental study on spectral beam combining with external cavity based on transmission grating.Using a series of cylindrical transform lenses with different focal lengths,spectral beaming combining efficiency is greatly improved,and the results of wavelength intervals are consistent with the theoretical calculations.With the injection current of 90 A,a 75.1 W cw 930 nm output power with wavelength span of 18.6 nm and spectral beam combining efficiency of 92.7%is achieved,the beam parameter product is 5.77 mm·mrad.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFA0300300 and 2017YFA0302900the Strategic Priority Research Program(B)of Chinese Academy of Sciences under Grant Nos XDB07020300and XDB25000000+2 种基金the National Basic Research Program of China under Grant No 2015CB921300the National Natural Science Foundation of China under Grant Nos 11334010 and 11534007the Youth Innovation Promotion Association of Chinese Academy of Sciences under Grant No 2017013
文摘By partially doping Pb to effectively suppress the superstructure in single-layered cuprate Bi_2Sr_2CuO_(6+δ)(Pb-Bi2201) and annealing them in vacuum or in high pressure oxygen atmosphere, a series of high quality Pb-Bi2201 single crystals are obtained with T_c covering from 17 K to non-superconducting in the overdoped region. High resolution angle resolved photoemission spectroscopy measurements are carried out on these samples to investigate the evolution of the Fermi surface topology with doping in the normal state. Clear and complete Fermi surfaces are observed and quantitatively analyzed in all of these overdoped Pb-Bi2201 samples. A Lifshitz transition from holelike Fermi surface to electron-like Fermi surface with increasing doping is observed at a doping level of ~0.35. This transition coincides with the change that the sample undergoes superconducting-to-non-superconducting states.Our results reveal the emergence of an electron-like Fermi surface and the existence of a Lifshitz transition in heavily overdoped Bi2201 samples. This provides important information in understanding the connection between the disappearance of superconductivity and the Lifshitz transition in the overdoped region.
基金supported by the National Natural Science Foundation of China (No. 11675273)the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA10011102)
文摘A database system,known as the large PMT characterization and instrumentation database system(LPMT-CIDS),was designed and implemented for the Jiangmen Underground Neutrino Observatory(JUNO).The system is based on a Linux+Apache+MySQL+PHP(LAMP)server and focuses on modularization and architecture separation.It covers all the testing stages for the 20-inch photomultiplier tubes(PMTs)at JUNO and provides its users with data storage,analysis,and visualization services.Based on the successful use of the system in the 20-inch PMT testing program,its design approach and construction elements can be extended to other projects.
基金the National Natural Science Foundation of China under Grant Nos 61505226 and 61535013the Fund of Chinese Academy of Sciences under Grant No 6141A01071701
文摘We report a high conversion efficiency Q-switched Nd:YVO_4/KTiOAsO_4(KTA) intracavity optical parametric oscillator(IOPO) operating near 3.5 um based on direct 880 nm laser diode(LD) pumping. A maximum average idler output power of 2.6 W with a pulse width of about 7.9 ns is achieved under an absorbed LD power of 45.4 W at a pulse repetition rate(PRR) of 10 kHz. The maximum optical-optical conversion efficiency from LD power to OPO mid-infrared(MIR) output of 6.74% is achieved. To our knowledge, this is the highest conversion efficiency for a KTA-IOPO by exploiting a Q-switched laser as the parent fundamental pump source. The beam quality factors M^2 of the MIR beam at the full output power with a PRR of 10 kHz are within 2.12 in both the horizontal and vertical directions, indicating a near Gaussian mode.
基金Project supported by the National Natural Science Foundation Program of China(Grant Nos.11504389 and 61505226)the National Key Research Development Program of China(Grant Nos.2016YFB040203 and 61535013)the National Development Project for Major Scientific Research Facility of China(Grant No.ZDYZ2012-2)
文摘We report on the experimental investigation and theoretical analysis of a nanosecond pulse high power ultraviolet（UV） 278 nm laser by fourth-harmonic generation（FHG） of a 1112-nm Nd：YAG amplifier in LiB3O5（LBO） and CsB3O5（CBO） crystals. The UV laser delivers a maximum average power of 10.3 W at 278 nm with peak power of 36.8 k W under input pump power of 41 W at 556 nm. This is, to the best of our knowledge, the highest output power at the specific UV wavelength of 278 nm. We also performed the theoretical investigation on the FHG with a model in the Gaussian approximation of both spatial and temporal profiles, especially accounting for the two-photon absorption effect in CBO crystal for the first time. The average output power, pulse width, and beam spatial distribution of the UV laser were simulated. The theoretical calculations are in close agreement with the experimental results.
基金Project supported by the National Natural Science Foundation of China(Grant No.62005215)。
文摘A novel high-energy picosecond optical parametric oscillator(OPO)was realized by placing an OPO in a secondharmonic(SH)cavity.In a proof-of-principle experiment,we demonstrated excellent burst energy of 45μJ for the OPO signal at 900 nm that operates at a pulse repetition rate of 10 k Hz and a pulse width of 46.8 ps.The beam quality was measured as M_(x)^(2)=1.44 and M_(y)^(2)=1.40 in the orthogonal directions,corresponding to an average beam factor M^(2)=1.42.So far,this study is the first to investigate high-energy ps OPO synchronously pumped in a second-harmonic cavity.
基金Supported by the National Natural Science Foundation of China under Grant No 11574367the National Basic Research Program of China under Grant Nos 2013CB921904 and 2015CB921300+2 种基金the National Key Research and Development Program of China under Grant No 2016YFA0300600the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB07020300the US Department of Energy under Grant No DE-SC0014208
文摘WTe2 has attracted a great deal of attention because it exhibits extremely large and non-saturating magnetore- sistance. The underlying origin of such a giant magnetoresistance is still under debate. Utilizing laser-based angle-resolved photoemission spectroscopy with high energy and momentum resolutions, we reveal the complete electronic structure of WTe2. This makes it possible to determine accurately the electron and hole concentrations and their temperature dependence. We find that, with increasing the temperature, the overall electron concen- tration increases while the total hole concentration decreases. It indicates that the electron-hole compensation, if it exists, can only occur in a narrow temperature range,and in most of the temperature range there is an electron-hole imbalance. Our results are not consistent with the perfect electron-hole compensation picture that is commonly considered to be the cause of the unusual magnetoresistance in WTe2. We identify a fiat band near the Brillouin zone center that is close to the Fermi level and exhibits a pronounced temperature dependence. Such a fiat band can play an important role in dictating the transport properties of WTe2. Our results provide new insight on understanding the origin of the unusual magnetoresistance in WTe2.
文摘Haemangiopericytoma(HPC) is a rare vascular tumor with borderline malignancy, considerable histological variability, and unpredictable clinical and biological behavior. HPC can present a diagnostic challenge because of its indeterminate clinical, radiological, and pathological features. HPC generally presents in adulthood and is equally frequent in both sexes. HPC can arise in any site in the body as a slowly growing and painless mass. The precise cell type origin of HPC is uncertain. One third of HPCs occur in the head and neck areas. Exceptional cases of hemangioblastoma arising outside the head and neck areas have been reported, but little is known about their clinicopathologic and immunohistochemical features. This study reports on a case of a large sacro-anterior HPC in a 65-year-old male.
基金Supported by the National Key Research and Development Program of China under Grant No 2016YFA0300300the National Natural Science Foundation of China under Grant No 11334010+1 种基金the National Basic Research Program of China under Grant No2015CB921300the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB07020300
文摘We carry out detailed momentum-dependent and temperature-dependent measurements on Bi_(2)Sr_(2)CaCu_(2)O_(8+δ)(Bi2212)superconductor in the superconducting and pseudogap states by super-high resolution laser-based angleresolved photoemission spectroscopy.The precise determination of the superconducting gap for the nearly optimally doped Bi2212(T_(c)=91 K)at low temperature indicates that the momentum-dependence of the superconducting gap deviates from the standard d-wave form(cos(2Φ)).It can be alternatively fitted by including a high-order term(cos(6Φ))in which the next nearest-neighbor interaction is considered.We find that the band structure near the antinodal region smoothly evolves across the pseudogap temperature without a signature of band reorganization which is distinct from that found in Bi_(2)Sr_(2)CuO_(6+δ)superconductors.This indicates that the band reorganization across the pseudogap temperature is not a universal behavior in cuprate superconductors.These results provide new insights in understanding the nature of the superconducting gap and pseudogap in high-temperature cuprate superconductors.
基金supported by the National Natural Science Foundation of China (31601333)the Doctoral Fund Southwest University (SWU118010)+1 种基金the National Program on Key Basic Research Project of China (973 Program: 2015CB150201)the Fundamental Research Funds for the Central Universities (XDJK2017B036)
文摘Glucosinolates are amino acid-derived secondary metabolites that act as chemical defense agents against pests.However,the presence of high levels of glucosinolates severely diminishes the nutritional value of seed meals made from rapeseed(Brassica napus L.).To identify the loci affecting seed glucosinolate cont ent(SGC),we con ducted genome-wide resequencing in a population of 307 diverse B.napus accessions from the three B.napus ecotype groups,namely,spring,winter,and semi-winter.These resequencing data were used for a genome-wide association study(GWAS)to identify the loci affecting SGC.In the three ecotype groups,four comm on and four ecotype-specific haplotype blocks(HBs)were significantly associated with SGC.To identify candidate genes controlling SGC,transcriptome analysis was carried out in 36 accessions showing extreme SGC values.Analyses of haplotypes,genomic variation,and candidate gene expression pointed to five and three candidate genes in the common and spring group-specific HBs,respectively.Our expression analyses dem on strated that additive effects of the three candidate genes in the spring group-specific HB play important roles in the SGC of B.napus.
基金supported by the National Natural Science Foundation of China (grant No. 31371318)the National Basic Research Program of China (grant No. 2011CB100703)the State Key Laboratory of Plant Genomics (grant No. SKLPG2011B0105)
文摘Endogenous small RNAs are newly identified players in plant immune responses, yet their roles in rice （Oryza sativa） responding to pathogens are still less understood, especially for pathogens that can cause severe yield losses. We examined the small RNA expression profiles of rice leaves at 2, 6, 12, and 24 hours post infection ofXanthomonas oryzae pv. oryzae （Xoo） virulent strain PXO99, the causal agent of rice bacterial blight disease. Dynamic expression changes of some miRNAs and trans-acting siRNAs were identified, together with a few novel miRNA targets, including an RLK gene targeted by osa-miR159a. 1. Coordinated expression changes were observed among some small RNAs in response to Xoo infection, with small RNAs exhibiting the same expression pattern tended to regulate genes in the same or related signaling pathways, including auxin and GA signaling pathways, nutrition and defense-related pathways. These findings reveal the dynamic and complex roles of small RNAs in rice-Xoo interactions, and identify new targets for regulating plant responses to Xoo.
基金Project supported by the National Development Project for Major Scientific Research Facility(No.ZDYZ2012-2)the National Instrumentation Program(No.2012YQ120048)
文摘We briefly review recent results on photoemission spectroscopy based on the deep and vacuum ultraviolet diode pumped solid-state lasers which we have developed.Cascaded second harmonic generation with the nonlinear crystal KBe2BO3F2(KBBF)is used to generate deep ultraviolet and vacuum ultraviolet laser radiation,which complements traditional incoherent light sources such as gas discharge lamps and synchrotron radiation,and has greatly improved resolution with respect to energy,momentum,and spin of photoemission spectroscopy.Many new functions have been developed with the advantages of high photon energy,narrow linewidth,high photon flux density,and so on.These have led to the observation of various new phenomena and the amassment of new data in the fields of high temperature superconductivity,topological electronics,Fermi semi-metals,and so forth.These laser systems have revived the field of photoemission spectroscopy and provided a new platform in this frontier research field.
基金funded by National Key Re-search and Development Project of China(No.2018YFD0200802).
文摘The insect nicotinic acetylcholine receptor(nAChR)is a pentameric channel protein and also a target for neonicotinoids.There are few reported studies on the molecular interactions of Leptinotarsa decemlineata nAChRs with neonicotinoids.In this study,we analyzed the response of acetylcholine and neonicotinoids(thiamethoxam[TMX],imidacloprid[IMI],and clothianidin[CLO])on hybrid receptors constructed by nAChRα1 andα8 subunits of L.decemlineata(Ldα1 and Ldα8)co-expressed with ratβ2 subunit(rβ2)at different capped RNA(cRNA)ratios in Xenopus oocytes.In addition,we evaluated the expression changes of Ldα1 and Ldα8 after median lethal dose of TMX treatment for 72 h by quantitative polymerase chain reaction(qPCR).The resulting functional nAChRs Ldα1/rβ2 and Ldα1/Ldα8/rβ2 showed different pharmacological characteristics.The neonicotinoids tested showed lower agonist affinity on Ldα1/Ldα8/rβ2 compared to Ldα1/rβ2 at same ratios of subunit cRNAs.The sensitivities of neonicotinoids tested for Ldα1/rβ2 and Ldα1/Ldα8/rβ2 at cRNA ratios of 5:1,1:1 and 5:5:1,1:1:1,respectively,were lower than those for nAChRs at ratios of 1:5 and 1:1:5,respectively,whereas the values of maximum response(Imax)varied.For Ldα1/Ldα8/rβ2,a reduction of Lda8 cRNA resulted in increased sensitivity to IMI and decreased sensitivity to TMX.The expression of Ldα1 and Ldα8 significantly decreased in adults by 82.12%and 47.02%,respectively,while Ldα8 was significantly upregulated by 2.44 times in 4th instar larvae after exposure to TMX.We infer that Ldα1 and Ldα8 together play an important role in the sensitivity of L.decemlineata to neonicotinoids.
